Halbarn Iron-Fur is a Nord blacksmith initially found at Bujold's Retreat while battling for control over Thirsk Mead Hall. If the quest Retaking Thirsk is completed, he relocates to the mead hall along with the others. If you speak to him after completing the quest, he will ask you to do him a favor by collecting some items for him. If you do so, he becomes a potential marriage candidate.